Lignin-Containing Cellulose Nanofibrils from TEMPO-Mediated Oxidation of Date Palm Waste: Preparation, Characterization, and Reinforcing Potential

High-Lignin-Containing Cellulose Nanofibrils from Date Palm Waste Produced by Hydrothermal Treatment in the Presence of Maleic Acid

Lignin-containing cellulose nanofibrils (LCNFs) have attracted great attention because the presence of lignin brought additional merits to cellulose nanofibrils including hydrophobicity, ultraviolet (UV)-shielding capacity, and reduced water sensitivity. In the present work, LCNFs with lignin content up to 21 wt % were prepared with a high yield exceeding 70 wt %, from neat date palm waste, by a hydrothermal treatment (HTT) at 120-150 °C in the presence of 20-30 wt % maleic acid, followed by high-pressure homogenization. The chemical composition, degree of polymerization, morphology, and colloidal and rheological properties of the LCNFs were investigated to understand how the HTT in the presence of MA affected the properties of the resulting LCNFs. Nanopapers prepared from the LCNF suspensions exhibited mechanical properties lower than those from lignin-free CNF-based nanopapers, yet with decreased hydrophilicity. A mechanism explaining how the HTT in the presence of MA facilitated the disintegration of the biomass into nanoscale material was proposed. Overall, the present work demonstrated a feasible and scalable approach for the sustainable production of LCNF suspensions from neat agricultural residues, with a high yield and a high lignin content, without any need to perform a preliminary partial delignification.

Lignocellulose nanofibrils/guar gum-based ethylene scavenging composite film integrated with zeolitic imidazolate framework-8 for food packaging

Ethylene, a ripening hormone, is critical in limiting the shelf life of fresh produce, specifically climacteric fruits and vegetables. A simple and benign fabrication approach is used to transform sugarcane bagasse, an agro-industrial waste into lignocellulosic nanofibrils (LCNF). In this investigation, biodegradable film was fabricated using LCNF (extracted from sugarcane bagasse) and guar gum (GG) which was reinforced with zeolitic imidazolate framework (ZIF)-8/zeolite. The LCNF/GG film not only acts as a biodegradable matrix to hold the ZIF-8/zeolite composite, but also possesses ethylene scavenging, antioxidant, and UV-blocking properties. The characterization results suggested that pure LCNF showed antioxidant activity of around 69.55 %. The LCNF/GG/MOF-4 film has shown lowest UV-transmittance (5.06 %) and highest ethylene scavenging capacity (40.2 %) among all the samples. After 6 days of storage at 25 ± 2 °C, packaged control bananas samples underwent significant degradation. In contrast, a banana package consisting of LCNF/GG/MOF-4 film maintained their high quality in terms of colour. Fabricated novel biodegradable film has potential application prospects for being used in prolonging the shelf life of fresh produce.

Preparation, Characterization and Industrial Application of Nanocellulose

The international research community has made significant efforts in the production, characterization, and application of cellulose nanofibers (CNFs) in many sectors [...].

Mechanically strong nanopapers based on lignin containing cellulose micro- and nano-hybrid fibrils: Lignin content-fibrils morphology-strengthening mechanism

Lignin-containing cellulose nanopapers are emerging multifunctional materials in the fields of coatings, films, and packaging. However, the forming mechanism and properties of nanopapers with various lignin content have not been thoroughly studied. In this work, a mechanically strong nanopaper was fabricated based on lignin-containing cellulose micro- and nano-hybrid fibrils (LCNFs). The influence of lignin content and fibrils morphology on the formation process of nanopapers was investigated to understand the strengthening mechanism of nanopapers. LCNFs with high lignin content provided nanopapers with intertwined micro- and nano-hybrid fibrils layers with small layer spacing, while LCNFs with low lignin content offered nanopapers interlaced nanofibrils layers with large layer spacing. Although lignin was expected to interfere with hydrogen bonds between fibrils, the uniformly distributed lignin contributed to the stress transfer between fibrils. Due to the good coordination between microfibrils, nanofibrils and lignin (as network skeleton, filler and natural binder, respectively), the well-designed LCNFs nanopapers with lignin content of 14.5 % showed excellent mechanical properties, including tensile strength (183.8 MPa), Young's modulus (5.6 GPa) and elongation (9.2 %). This work deeply reveals the relationship between lignin content, morphology and strengthening mechanism of nanopapers, and providing theoretical guidance for employing LCNFs as structural and reinforcing materials to design robust composites.